Quartz fiber electroscopes



April 17, 1956 R. P. HENDERsoN QUARTZ FIBER ELECTROSCOPES 2 Sheets-Sheet l Filed Dec. 14, 1951 ttorney April 17, 1956 R. P. HENDRsoN 2,7425?? QUARTZ FIBER ELECTROSCOPES Filed Dec. 14, 1951 2 Sheets-Shem 2 United States Patent O 2,742,577 QUARrz FIBER ELEcrRoscoPEs Ronald Paterson Henderson, Abingdon, England Application December 14, 1951, Serial No. 261,664

4 Claims. (Cl. ZSO-83.3)

This invention relates to quartz fibre electroscopes.

Quartz fibre electroscopes have use as monitoring instruments for personnel engaged in localities where a radiation hazard exists and such electroscopes are usually designed to be suitable for carrying unobtrusively on the person. Known forms include one constructed in a body similar in form to a wrist watch case and another' is constructed in a tube comparable in size and shape to that of a fountain pen.

A quartz fibre electroscope consists essentially of an airtight container inside which are mounted a quartz fibre system supported from a high grade insulator and a scale over which a flexible fibre of the fibre system moves. In the walls of the container there are provided a window to illuminate the scale and the flexible fibre and an optical system to provide enlarged images of the fibre and scale. The container may be made of metal or be provided with a metallic inner coating. The fibre system comprises a fine flexible quartz fibre of a few mcrons in thickness, which is supported in close proximity to another fibre or wire of greater thickness which is rigid. The fibres are metallised.

In the broadest aspect the invention comprises a quartz fibre electroscope having means for charging the electroscope by a corona discharge.

In a perferred form of the invention the charging means comprises a metal or metallised fibre such as a metallised quartz fibre.

Corona charging is advantageous in that the charging of the electroscope is carried out without obtaining contact with the fibre system or its support and the electroscope can therefore be constructed without a protective cap or device to prevent wrongful discharging.

Electroscopes embodying the invention are now described with. reference to the drawings.

Fig. 1 is a longitudinal sectional elevation of one form.

Fg. 2 is a transverse section on the line II -II of Fg. 1.

Fig. 3 shows the presentation of the images of the scale and flexible fibre.

Fig. 4 is a longitudinal sectional elevation of another form.

Fig. 5 is a transverse section on the line V -V of Fig. 4.

Fig. 6 is a side elevation of a finger ring holding an electroscope of the type shown in Figs. 4 and 5. i

Fig. 7 is a front elevation of Fig. 6.

In Figs. 1 and 2 a tubular aluminium container 1 of about 8 mm. external diameter and 20 mm. long has provided at one end a bifocal lens 2 having lens elements 3, 4. At the other end of the container 1 there is a lighttransmitting insulator 5, and a disc 6 having an aperture 7. The insulator and disc are secured by the spun ends 8 of the container 1. Moulded in the insulator there is a scale 9, a charging electrode support 10 and a fibre system support 11. The scale consists of etched figures on a glass plate. The supports V10 and 11 are constructed from copper tube. Crimped into the support 10 there is a charging electrode comprising an aluminium Wire 12 carrying a fine metallised quartz fibre 13 which extends in the direction of support 11 so that a corona discharge may be set up across the space be- 2,742,577 Patented Apr. 17, 1956 tween the fibre and support. A fibre system 14 consists of a rigid metallised fibre 15 and a flexible metallised fibre 16 carried in an aluminium Wire 17 crirnped into the support 11.

Light, to illuminate the scale 9 and fibre 16, enters the electroscope through the aperture 7 in the disc 6. The charging electrode support 10 and Wire 12 are exposed at their ends in the aperture 7 for charging purposes. The fibre system is charged to a potentiall of about volts relative to the container 1 by the application of a potential of about 1,000 volts to the support 10. The charging process is carried out until the flexible fibre 16 is observed to more over a full scale deflection.

In Fig. 3 the fibre Vimage 16' viewed by the element 3 of lens 2 is shown as contiguous to the scale image 9' viewed by the element 4.

Figs. 4 and 5 show modifications over Figs. 1 and 2. The container 18 is oval in form to provide more accommodation along the direction Vof the major axs without substantially altering the cross-sectional area. Charging of the electroscope is effected by a corona charging fibre 19 supported on a Wire 20 embedded in a polystrene nsulator 21 in the end 22 of the container. A hole 23 is provided in the insulator 21 so that a metal probe may be inserted to applyva charging potential to the wire 20. The probe charges the metal sleeve 24 which is moulded in a polystyrene sheath 25. The moulded sheath 25 also includes the bifocal lens 26. The fibre system 27 is'similar to system 14 of Figs. 1 and 2. It consists of a relatively rigid metallised fibre 28 and a flexible metallised fibre 29 carried in an aluminium wre 30 fixed in the end 22. A polystyrene window 31 is also moulded into the end 22 and the window carries a scale 32.

Figs. 6 and 7 show the electroscope of Figs. 5 and 6 fitted into a finger ring 33.

I claim:

1. A quartz fibre electroscope having charging means comprising a pointed electrode fixedly supported with respect to the electroscope, in close proximity to the element to be charged; and means for providing electrical contact with the electrode from outside the electroscope.

2. A quartz fibre electroscope comprising, an airtight chamber, a first element fixedly mounted to said chamber and having mounted thereon a flexible metallised quartz fibre, a second element fixedly mounted to said chamber, said second element including a fine metallic charging member fixedly maintained, spaced and insulated from said fibre, and means for applying a voltage to said charging member from outside said chamber, whereby said electroscope is charged by a corona discharge from said charging member.

3. An electroscope according to claim 2 in which said charging member comprises a metallised quartz fibre.

4. A quartz fibre electroscope comprising a hollow electrode, a metallised quartz fibre system mounted within and insulated from said electrode to constitute a second electrode, a charging electrode insulated from said first and second electrode, and closure means for said hollow electrode to provide an airtight chamber wherein said charging electrode extends from the exterior of said chamber and terminates in a fine point secured in fixed spaced relatonship with one of said electrodes.

References Cited in the file of this patent UNITED STATES PATENTS 1,059,095 Whitehead Apr. 15, 1913 1,289,068 Allcutt Dec. 31, 1918 1,933,063 Kolhorster Oct. 31, 1933 2,022,117 Lauritsen Nov. 26, 1935 

1. A QUARTZ ELECTROSCOPE HAVING CHARGING MEANS COMPRISING A POINTED ELECTRODE FIXEDLY SUPPORTED WITH RESPECT TO THE ELECTROSCOPE, IN CLOSE PROXIMITY TO THE ELEMENT TO BE CHARGED; AND MEANS FOR PROVIDING ELECTRICAL CONTACT WITH THE ELECTRODE FROM OUTSIDE THE ELECTROSCOPE. 